Overload protection device

ABSTRACT

An overload protection device includes a power detection unit, a processing unit, a breaker unit and a warning unit. According to the power value detected by the power detection unit, the processing unit determines whether to drive the breaker unit and determines the warning level of the warning unit. Accordingly, the overload protection device can provide overload protection and achieve warning effect.

FIELD OF THE INVENTION

The present invention relates generally to an overload protectiondevice, and more particularly to an overload protection device withwarning function.

BACKGROUND OF THE INVENTION

In order to avoid danger caused by fusion of electrical wire under toohigh electrical power, a domestic general power switch is often equippedwith a fuse. The fuse has a melting point lower than that of theelectrical wire (copper wire). Therefore, in case of an overload, thefuse will fuse first under high heat to interrupt power supply and thusavoid short-circuit. However, once the fuse fuses, it is necessary toreplace it with a new one. This is quite inconvenient to the resident.Therefore, most of the current general power switches are alreadyprovided with spring switches instead of the fuses. The spring switchworks in the principle that in case of overload, the spring switch willautomatically bound up to break the power supply circuit. When it isdesired to recover the power supply, it is necessary to shift the springswitch back to its home position. Such design is able to avoid danger ofshort-circuit caused by overload. However, after a period of use,elastic fatigue of the spring switch is likely to take place. In thiscase, a serious consequence may happen. Therefore, the above overloadprotection switch can hardly reliably provide an overload protectioneffect. Moreover, the resident cannot be aware of whether the currentpower supply is safe, close to an overload state or already in anoverload state. In this case, the power supply will continue. This maylead to a dangerous situation.

SUMMARY OF THE INVENTION

It is therefore a primary object of the present invention to provide anoverload protection device with warning effect.

According to the above and other objects, the overload protection deviceof the present invention includes: a power detection unit for detectingthe value of power output by an external power supply; a processing unitelectrically coupled with the power detection unit and preset with apower limitation value; a breaker unit electrically coupled with theprocessing unit; and a warning unit electrically coupled with theprocessing unit. In the case the value of the power is smaller than thepower limitation value, the processing unit controls the warning unit togenerate a first warning signal. In the case the value of the power islarger than the power limitation value, the processing unit controls thewarning unit to generate a second warning signal and activate thebreaker unit to interrupt power supply from the external power supply.

BRIEF DESCRIPTION OF THE DRAWINGS

The structure and the technical means adopted by the present inventionto achieve the above and other objects can be best understood byreferring to the following detailed description of the preferredembodiments and the accompanying drawings, wherein:

FIG. 1 is a block diagram showing the layout of the overload protectiondevice of the present invention; and

FIG. 2 is a block diagram of the overload protection device of thepresent invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Please refer to FIGS. 1 and 2. FIG. 1 is a block diagram showing thelayout of the overload protection device of the present invention. FIG.2 is a block diagram of the overload protection device of the presentinvention. The overload protection device 20 of the present invention isarranged between an external power supply (civil power) 10 and a wallsocket 30 or a socket of an extension cable. The overload protectiondevice 20 mainly includes a power detection unit 23, a processing unit22, a breaker unit 25 and a warning unit 24. According to the powervalue detected by the power detection unit 23, the processing unit 22determines whether to drive the breaker unit 25 and determines thewarning level of the warning unit 24.

For example, the power detection unit 10 is electrically coupled withthe external power supply (civil power) 10 to detect the value of thepower output by the external power supply 10. The processing unit 22 iselectrically coupled with the power detection unit 23 and preset with apower limitation value (such as 1500 watts). The warning unit 24 and thebreaker unit 25 are both electrically coupled with the processing unit22. The warning unit 24 is a light-emitting diode (LED) or a loudspeaker. In the case the power detection unit 23 detects that the valueof the power output by the external power supply (civil power) 10 issmaller than the power limitation value, the processing unit 22 willcontrol the warning unit 24 to generate a first warning signal (such asto make the LED unlighted or simply flicker once or make the loudspeaker silenced or simply beep once). In the case the value of thepower is larger than the power limitation value (1500 watts), theprocessing unit 22 will control the warning unit 24 to generate a secondwarning signal (such as to make the LED continuously flicker or make theloud speaker continuously beep). In the meantime, the breaker unit 25 isactivated to interrupt power supply from the external power supply 10.Accordingly, when the power is cut off, a user can know from the warningunit 24 why the power is cut off. The user can judge whether it is thecase of a blackout or an overload and then make a proper management.

In addition, the overload protection device 20 of the present inventionhas a better warning function. The warning unit 24 further includes afirst indicator lamp 241, a second indicator lamp 242, a third indicatorlamp 243 and a fourth indicator lamp 244. Also, the power limitationvalue is correspondingly classified into first to fourth power levels(500 W, 1000 W, 1300 W, 1500 W). In the case the value of the poweroutput by the external power supply (civil power) 10 is smaller than thefirst power level (500 W), the processing unit 22 drives the firstindicator lamp 241 of the warning unit 24 to emit such as green light toshow that the current power supply is quite safe. In the case the valueof the power output by the external power supply (civil power) 10 isbetween the first power level (500 W) and the second power level (1000W), the processing unit 22 drives the second indicator lamp 242 of thewarning unit 24 to emit such as yellow light to show that the currentpower supply is slightly higher but still within a safety range. In thecase the value of the power output by the external power supply (civilpower) 10 is between the second power level (1000 W) and the third powerlevel (1300 W), the processing unit 22 drives the third indicator lamp243 of the warning unit 24 to emit such as red light to show that thecurrent power supply is too high and no further load should be added. Inthe case the value of the power output by the external power supply(civil power) 10 is larger than the fourth power level (1500 W), theprocessing unit 22 drives the fourth indicator lamp 244 of the warningunit 24 to emit such as red light in a flickering manner to show thatthe current power supply is overloaded and the power from the externalpower supply 10 is cut off. Accordingly, a resident or a user can judgethe current power supply from the external power supply 10 for the loadsby means of the warning unit 24 and consider how to adjust the number ofthe loads.

The above embodiments are only used to illustrate the present invention,not intended to limit the scope thereof. It is understood that manychanges and modifications of the above embodiments can be made withoutdeparting from the spirit of the present invention. The scope of thepresent invention is limited only by the appended claims.

1. An overload protection device comprising: a power detection unit fordetecting the value of power output by an external power supply; aprocessing unit electrically coupled with the power detection unit andpreset with a power limitation value; a breaker unit electricallycoupled with the processing unit; and a warning unit electricallycoupled with the processing unit, in the case the value of the power issmaller than the power limitation value, the processing unit controllingthe warning unit to generate a first warning signal, in the case thevalue of the power is larger than the power limitation value, theprocessing unit controlling the warning unit to generate a secondwarning signal and activating the breaker unit to interrupt power supplyfrom the external power supply.
 2. The overload protection device asclaimed in claim 1, wherein the warning unit is a light-emitting diode.3. The overload protection device as claimed in claim 1, wherein thewarning unit is a loud speaker.
 4. The overload protection device asclaimed in claim 1, wherein the power limitation value is classifiedinto a first power level, a second power level, a third power level anda fourth power level, the warning unit including a first indicator lamp,a second indicator lamp, a third indicator lamp and a fourth indicatorlamp, in the case the value of the power is smaller than the first powerlevel, the processing unit driving the first indicator lamp to emitlight, in the case the value of the power is between the first powerlevel and the second power level, the processing unit driving the secondindicator lamp to emit light, in the case the value of the power isbetween the second power level and the third power level, the processingunit driving the third indicator lamp to emit light, in the case thevalue of the power is larger than the fourth power level, the processingunit driving the fourth indicator lamp to emit light and the power fromthe external power supply being cut off.